Apart from their obvious 19th-century Russian connections, the common denominator between the three works here, all gorgeously played by the Nash Ensemble, is a strange one. The scoring of all of them includes two cellos — Glazunov's concept of the string quintet follows Boccherini and Schubert rather than Mozart and Brahms in preferring two cellos to two violas, while Arensky's Second String Quartet replaces the standard pair of violins with two of its lower-pitched sibling. In fact, the Arensky, composed in 1894 as a memorial to Tchaikovsky, is easily the most striking of these little performed pieces, with the second cello tipping the centre of gravity very much towards the middle and lower registers and making the textures sombre and elegiac. The other two are early works: Borodin's sextet from 1860, composed when he was still studying to be a chemist rather than a composer, has just two movements, typically tuneful and rather Germanic, while Glazunov's 1892 quintet is fluent and ingratiating if rather unmemorable. Like the rest of the disc, though, it's delivered with such energy and relish that hardly matters.